lock annotations for MemPoolAccept functions

We should already have the mempool lock when entering
CheckInputsFromMempoolAndCache

Author: glozow

src/validation.cpp

@@ -407,21 +407,17 @@ static void UpdateMempoolForReorg(CTxMemPool& mempool, DisconnectedBlockTransact
 // Used to avoid mempool polluting consensus critical paths if CCoinsViewMempool
 // were somehow broken and returning the wrong scriptPubKeys
 static bool CheckInputsFromMempoolAndCache(const CTransaction& tx, TxValidationState& state, const CCoinsViewCache& view, const CTxMemPool& pool,
-                 unsigned int flags, PrecomputedTransactionData& txdata) EXCLUSIVE_LOCKS_REQUIRED(cs_main) {
+                 unsigned int flags, PrecomputedTransactionData& txdata) EXCLUSIVE_LOCKS_REQUIRED(cs_main, pool.cs) {
     AssertLockHeld(cs_main);
-
-    // pool.cs should be locked already, but go ahead and re-take the lock here
-    // to enforce that mempool doesn't change between when we check the view
-    // and when we actually call through to CheckInputScripts
-    LOCK(pool.cs);
+    AssertLockHeld(pool.cs);
 
     assert(!tx.IsCoinBase());
     for (const CTxIn& txin : tx.vin) {
         const Coin& coin = view.AccessCoin(txin.prevout);
 
-        // AcceptToMemoryPoolWorker has already checked that the coins are
-        // available, so this shouldn't fail. If the inputs are not available
-        // here then return false.
+        // This coin was checked in PreChecks and MemPoolAccept
+        // has been holding cs_main since then.
+        Assume(!coin.IsSpent());
         if (coin.IsSpent()) return false;
 
         // Check equivalence for available inputs.
@@ -502,21 +498,21 @@ class MemPoolAccept
 
     // Run the script checks using our policy flags. As this can be slow, we should
     // only invoke this on transactions that have otherwise passed policy checks.
-    bool PolicyScriptChecks(ATMPArgs& args, const Workspace& ws, PrecomputedTransactionData& txdata) EXCLUSIVE_LOCKS_REQUIRED(cs_main);
+    bool PolicyScriptChecks(ATMPArgs& args, const Workspace& ws, PrecomputedTransactionData& txdata) EXCLUSIVE_LOCKS_REQUIRED(cs_main, m_pool.cs);
 
     // Re-run the script checks, using consensus flags, and try to cache the
     // result in the scriptcache. This should be done after
     // PolicyScriptChecks(). This requires that all inputs either be in our
     // utxo set or in the mempool.
-    bool ConsensusScriptChecks(ATMPArgs& args, const Workspace& ws, PrecomputedTransactionData &txdata) EXCLUSIVE_LOCKS_REQUIRED(cs_main);
+    bool ConsensusScriptChecks(ATMPArgs& args, const Workspace& ws, PrecomputedTransactionData &txdata) EXCLUSIVE_LOCKS_REQUIRED(cs_main, m_pool.cs);
 
     // Try to add the transaction to the mempool, removing any conflicts first.
     // Returns true if the transaction is in the mempool after any size
     // limiting is performed, false otherwise.
     bool Finalize(ATMPArgs& args, Workspace& ws) EXCLUSIVE_LOCKS_REQUIRED(cs_main, m_pool.cs);
 
     // Compare a package's feerate against minimum allowed.
-    bool CheckFeeRate(size_t package_size, CAmount package_fee, TxValidationState& state)
+    bool CheckFeeRate(size_t package_size, CAmount package_fee, TxValidationState& state) EXCLUSIVE_LOCKS_REQUIRED(cs_main, m_pool.cs)
     {
         CAmount mempoolRejectFee = m_pool.GetMinFee(gArgs.GetArg("-maxmempool", DEFAULT_MAX_MEMPOOL_SIZE) * 1000000).GetFee(package_size);
         if (mempoolRejectFee > 0 && package_fee < mempoolRejectFee) {